docs: def is_reduced_grid(nc, variable):
      '''
      Returns True if the feature-type of the variable corresponds to a reduced
      horizontal grid.
  
      :param netCDF4.Dataset nc: An open netCDF dataset
      :param str variable: name of the variable to check
      '''
      axis_map = get_axis_map(nc, variable)
  
      if 'X' not in axis_map:
          return False
      if 'Y' not in axis_map:
          return False
      if 'C' not in axis_map:
          return False
  
      compressed_coordinates = axis_map['C']
      if len(compressed_coordinates) > 1:
          return False
      compressed_coordinate = axis_map['C'][0]
      for dim in nc.variables[compressed_coordinate].compress.split():
          if dim not in nc.dimensions:
              return False
      return True